John Connolly put his unique stamp on the serial-killer thriller in his five Charlie Parker novels, beginning with "Every Dead Thing" and most recently with "The Black Angel." Now he tries his hand at outright fantasy in The Book of Lost Things (Atria; 339 pages; $23).

After his mother dies of cancer during World War II, 12-year-old David finds solace in reading and the power of his imagination. But when his father remarries and has a baby with his new wife, the boy begins to feel as if he is being pushed out of the family. On the night of a German air strike, seemingly guided by his mother's voice, David finds himself thrust into a strange land populated by figures out of myth and fairy tales, including a kind huntsman, a legion of werewolves, a valiant knight and a trickster known as the Crooked Man. His only hope of survival is to find the exhausted king of the land and learn the secrets kept in the titular volume.

In preparation for this new novel, Connolly clearly brushed up on his Brothers Grimm and studied Bruno Bettelheim's "The Uses of Enchantment." The essential question, however, is: How many young-adult fantasies has Connolly read in the past 10 or 20 years?

Connolly distinguished his Parker books from run-of-the-mill crime novels by evocatively setting them in Maine and adding a whiff of the supernatural to their plots. "The Book of Lost Things" proves to be a competent, but not especially compelling, fantasy that could have been written by any number of other novelists. It pales in comparison to the output of people who deeply understand this genre, writers like Jane Yolen, Neil Gaiman or Diana Wynne Jones. Young David is a particularly bland protagonist, the issues he needs to resolve are all too obvious and his accidental arrival in the mythic wonderland recalls too strongly C.S. Lewis' Narnia books, but without all the Christian underpinnings.

Only occasionally -- as when he describes the sadistic tricks of the Crooked Man -- does Connolly achieve the narrative vitality that runs throughout his thrillers. "The Book of Lost Things" is a creditable experiment, but ultimately an unsuccessful one.

In The Thirteenth Tale (Atria; 407 pages; $26), first-time novelist Diane Setterfield evokes the shades of Daphne du Maurier, Henry James and the Bronte sisters in a literary mystery with unmistakably gothic sensibilities.

When Margaret Lea receives an invitation to write the authorized biography of best-selling novelist Vida Winter, she is more than a little nonplussed. An antiquarian bookseller with little interest in contemporary fiction and only a few publication credits on her resume, Lea can't fathom why she has been summoned by a reclusive author infamous for concocting conflicting stories about her past. Winter swears to tell her the truth, however, and Lea finds herself drawn into a wild tale of familial depravity, neglect and mistaken identity, a story that may impinge upon her own traumatic upbringing as the surviving member of a set of conjoined twins.

A mysterious fire, an abandoned infant, a fainting spell on the moors and a clue literally torn from "Jane Eyre" all figure into the solution of the puzzle that is Vida Winter's life. Depending on how you interpret "The Thirteenth Tale," there's even a ghost or two, justifying the novel's inclusion in this column. Setterfield breathes new life into these gothic cliches and delivers a thoroughly engaging novel that both slyly sends up and respectfully celebrates old-fashioned storytelling.

Los Gatos writer Rudy Rucker created a gonzo fable for all ages in his previous novel, "Frek and the Elixir." His latest, Mathematicians in Love (Tor, 364 pages; $24.95), is much more adult in theme but still percolates with off-the-wall characters and trippy extra-dimensional shenanigans.

When grad student Bela Kis helps devise a new theorem for predicting seemingly random behavior and then wins the affections of rhetoric major Alma Ziff, he figures he's got it made. Unfortunately, his thesis adviser suffers a mental breakdown, claiming to see giant cockroaches and flying conch shells beckoning him from within reflective surfaces. Then Bela loses Alma to his co-author and roommate, Paul Bridge. Worse, Bela and Paul's theorem falls into the hands of right-wing conspirators who plan to fix the local elections, a situation that indirectly leads to the murder of another young woman to whom both men are attracted.

What's the most logical way to fix these problems? Why, find a way to tunnel into another universe where some of these things never happened, of course! Nobody writes math-based science fiction like Rucker does. He keeps the tone light and the action playful, even as his characters grapple with the meaning of tragedy and the ultimate mechanics of the universe. You don't need to be able to solve a differential equation to enjoy "Mathematicians in Love," a definite high point in a Rucker's singular writing career.